I dont think there is a single BEST alternative. Each has it positives and negatives. Wind and solar work only when mother nature cooperates. Nuclear has radiation issues. Hydrogen, is expensive to produce in mass quantity. Bio fuels dont have a lot of energy per gallon and they tend to cause food prices to rise.
However, a combined approach is a good way to go. I also think that micro power is better. With todays tech, almost every home and office building could be a power generation plant. Thus the need for big central power plants would not be needed. Combine wind, solar and hydrogen to power your home and office. Its doable now.